IBC 714.2 Protection of structural members.(Newer 704)

[steveray]

I have a 4 and 5 story wood framed (IIIA and VA) buildings.....They don't technically meet the "light frame" exception (in the newer IBC) and I was wondering if anyone had input on these sections that talk about individual encasement and how to accomplish that in a platform frame structure? Still under plan review and I haven't quite gotten to those details yet, everything will be rated, but I do not believe there is a plan for individual encasement as of yet....Thanks in advance...

714.2 Protection of structural members. Protection of columns, girders, trusses, beams, lintels or other structural members that are required to have a fire-resistance rating shall comply with this section.
714.2.1 Individual protection. Columns, girders, trusses, beams, lintels or other structural members that are required to have a fire-resistance rating and that support more than two floors or one floor and roof, or support a load-bearing wall or a nonload-bearing wall more than two stories high, shall be individually protected on all sides for the full length with materials having the required fire-resistance rating. Other structural members required to have a fire-resistance rating shall be protected by individual encasement, by a membrane or ceiling protection as specified in Section 711, or by a combination of both. Columns shall also comply with Section 714.2.2.

This has been cleared up a bit in the newer code but it is still fuzzy to me...

Maybe they don't mean the same with "light frame construction" as "conventional light frame" in Ch 23....

 

[Francis Vineyard]

In the 2006 is written differently; does Table 601; footnote a. help?

 

[JBI]

Use Fire Retardant Treated Wood?

 

[mtlogcabin]

Light Frame Construction has limitations
Can't be used where I live for snow and seismic reasons mostly and the 40 psf floor loads kill most other projects

2308.2 Limitations.
Buildings are permitted to be constructed in accordance with the provisions of conventional light-frame construction, subject to the following limitations, and to further limitations of Sections 2308.11 and 2308.12.

1. Buildings shall be limited to a maximum of three stories above grade plane. For the purposes of this section, for buildings assigned to Seismic Design Category D or E, cripple stud walls shall be considered to be a story.

Exception: Solid blocked cripple walls not exceeding 14 inches (356 mm) in height need not be considered a story.

2. Maximum floor-to-floor height shall not exceed 11 feet, 7 inches (3531 mm). Bearing wall height shall not exceed a stud height of 10 feet (3048 mm).

3. Loads as determined in Chapter 16 shall not exceed the following:

3.1. Average dead loads shall not exceed 15 psf (718 N/m2) for combined roof and ceiling, exterior walls, floors and partitions.

Exceptions:

1. Subject to the limitations of Sections 2308.11.2 and 2308.12.2, stone or masonry veneer up to the lesser of 5 inches (127 mm) thick or 50 psf (2395 N/m2) and installed in accordance with Chapter 14 is permitted to a height of 30 feet (9144 mm) above a noncombustible foundation, with an additional 8 feet (2438 mm) permitted for gable ends.

2. Concrete or masonry fireplaces, heaters and chimneys shall be permitted in accordance with the provisions of this code.

3.2. Live loads shall not exceed 40 psf (1916 N/m2) for floors.

3.3. Ground snow loads shall not exceed 50 psf (2395 N/m2).

4. Vasd as determined in accordance with Section 1609.3.1 shall not exceed 100 miles per hour (mph) (44 m/s) (3-second gust).

Exception: Vasd as determined in accordance with Section 1609.3.1 shall not exceed 110 mph (48.4 m/s) (3-second gust) for buildings in Exposure Category B that are not located in a hurricane-prone region.

5. Roof trusses and rafters shall not span more than 40 feet (12 192 mm) between points of vertical support.

6. The use of the provisions for conventional light-frame construction in this section shall not be permitted for Risk Category IV buildings assigned to Seismic Design Category B, C, D, E or F.

7. Conventional light-frame construction is limited in irregular structures assigned to Seismic Design Category D or E, as specified in Section 2308.12.6.

 

[steveray]

JBI....Because FRTW is not noncombustible, I don't know that it is really "rated" that I would call it individually protected....But I will keep digging...

MT...That is what I was looking at because in the newer codes, the definition of "light frame construction" includes steel vs. CH 23 which addresses "CONVENTIONAL light frame"....Haven't looked through 22 yet to see if they have a light steel section there yet, not that it applies to my project...

 

[JBI]

Chapter 22 has a couple of sections for 'cold-formed' steel, 2210 and 2211. The latter is the 'light frame' section.

 

[steveray]

704.3 Protection of the primary structural frame other than columns. Members of the primary structural frame other than columns that are required to have protection to
achieve a fire-resistance rating and support more than two floors or one floor and roof, or support a load-bearing wall or a nonload-bearing wall more than two stories high, shall be
provided individual encasement protection by protecting them on all sides for the full length, including connections to other structural members, with materials having the required
fire-resistance rating.

Exception: Individual encasement protection on all sides shall be permitted on all exposed sides provided the extent of protection is in accordance with the required fire-resistance
rating, as determined in Section 703.

 All primary structural frames do not need to comply with this section. Only those primary structural frame members that are required to have a fire-resistance rating and support more than two floors, more than one floor and a roof, a bearing wall of any height or a nonload-bearing wall more than two stories high, are required to be protected by individual encasement.
Individual encasement, though not defined, is attained by using tested design assemblies that provide gypsum board applied directly to the member or to studs that are directly attached to all sides of the member, mastic and intumescent coatings, and sprayed fire-resistant materials. Individual encasement is required for the primary structural frame members receiving tributary loads from multiple levels in order to reduce the risk associated with catastrophic failure. The risk represented by structural collapse during a fire is significantly increased in multistory buildings, since the occupants require additional time of egress and a single structural element that supports multiple elements requires more conservative protection methods.


Seems like in the newer codes they have distinguished between primary frame and bearing walls (just like Table 601....The commentary above says: "a bearing wall of any height or a nonload-bearing wall more than two stories high, are required to be protected by individual encasement." How do you individually encase a wall? And it is even muddier as to beams and headers and when they become primary frame, not to mention load paths to figure out what is supporting what....Dang buildings over 2 stories....

 

[JBI]

If I build a stud wall, apply GWB to both sides, meet up with a GWB ceiling at the top and a floor at the bottom, that wall is encased on all sides.
The 'top' and 'bottom' of the plates are not 'sides'.

 

[steveray]

If I build a stud wall, apply GWB to both sides, meet up with a GWB ceiling at the top and a floor at the bottom, that wall is encased on all sides.
The 'top' and 'bottom' of the plates are not 'sides'.

And when I punch a window through it? How do I protect the header and jacks? When said wall is sitting on a rated floor, I would agree that it is rated on all sides....With "rated" construction, this seems like a nonissue, just trying to figure out the real intent.

Or... lets say I have a rated bearing wall inside an apartment. Not a fire barrier or partition, I could install a wicker door and jamb (by code), how is the structural rating being maintained?

2015 seems to recognize the rated construction aspect better....

704.4.1 Light-frame construction. Studs and boundary elements that are integral elements in load-bearing walls of light-frame construction shall be permitted to have
required fire-resistance ratings provided by the membrane protection provided for the load-bearing wall.
704.4.2 Horizontal assemblies. Horizontal assemblies are permitted to be protected with a membrane or ceiling where the membrane or ceiling provides the required fireresistance
rating and is installed in accordance with Section 711.

And thanks for the discussion guys!

 

[JBI]

The 'real intent' is to address columns and girders IMO, not repetitive member framing per se.

 

[steveray]

But when is a header a girder or beam or lentil....or any of those other terms they use to describe a member that bears multiple members? And when does a jack become a column?

 

[Francis Vineyard]

2015 IBC Handbook excerpt; "Where the column is located within a fire-resistance-rated wall assembly the mandated column protection must still be provided through individual encasement. It is not acceptable to simply place an unprotected column within a fire-resistance-rated wall assembly and consider the column as fire-resistant rated.

The code intends that the fire-resistive protection for primary structural frame members be applied to the individual structural member. This is based on the differences in both the testing procedure and the conditions of acceptance that were discussed in Section 703. In other words, the code does not intend that a primary structural frame member be protected by a wall assembly or fire-resistance-rated horizontal assembly, except as permitted by this section.

Under certain restrictions, the code allows the use of a floor/ceiling or roof/ceiling assembly to provide protection for structural members, rather than requiring that they be individually protected.

Floor joists and roof joists are examples of secondary members that are permitted to be protected by the horizontal assembly in which they are located. In light-frame construction, membrane protection is also permitted for studs and similar elements that are integral elements in load-bearing walls."

 

[steveray]

Thanks FV....Just seems kind of funny that I could have a 20' header (beam) and jacks (posts) "in" a bearing wall and have the membrane protection....

 

[Francis Vineyard]

Yes; but I think this exception provides relief in most cases; " . . . more than two floors or one floor and roof, or support a load-bearing wall or a nonload-bearing wall more than two stories high . . ."

 

[steveray]

I was thinking that, but I don't want to have to chase load paths through a building to determine what the fire rating of a member is....I also have been hesitant to write "How are you complying with IBC 714.2?" on my plan review too.....

 

[JBI]

The design professional should identify the load path(s) so the Code Official does not have to hunt them down.
Asking for clarification is a primary purpose of plan review. Never be afraid to ask.

 

[kopplin]

I need clarification of 704.3 Protection of the primary structural frame other than columns. Members of the primary structural frame other than columns that are required to have protection to achieve a fire-resistance rating and support more than two floors or one floor and roof, or support a load-bearing wall or a non-load-bearing wall more than two stories high, shall be provided individual encasement protection by protecting them on all sides for the full length, including connections to other structural members, with materials having the required fire-resistance rating.


Does the bolded phrase in fact mean MORE than two-floors or MORE than one floor and roof, not just a one floor and roof? So, 2 floors and roof?

Is this in a building code commentary somewhere?

 

[SH225]

I need clarification of 704.3 Protection of the primary structural frame other than columns. Members of the primary structural frame other than columns that are required to have protection to achieve a fire-resistance rating and support more than two floors or one floor and roof, or support a load-bearing wall or a non-load-bearing wall more than two stories high, shall be provided individual encasement protection by protecting them on all sides for the full length, including connections to other structural members, with materials having the required fire-resistance rating.


Does the bolded phrase in fact mean MORE than two-floors or MORE than one floor and roof, not just a one floor and roof? So, 2 floors and roof?

Is this in a building code commentary somewhere?

Commentary on that topic is attached.